Cylindrical cyclone centrifuges

ABSTRACT

Cylindrical cyclone centrifuges wherein the heavy phase outlet is controlled so as to obtain efficient separation of the heavy phase from the light phase in a feed such as oil well drilling mud having such components and so as to inhibit undesirable plugging of the outlet for the heavy phase.

United States Patent [191 Bobo [.451 July 8,1975

[ CYLINDRICAL CYCLONE CENTRIFUGES [76] Inventor: Roy A. Bobo, 2000 N.Loop West,

Suite 215, Houston, Tex. 77018 [22] Filed: Dec. 14, 1972 [21] Appl. No.:315,233

[52] US. Cl. 209/211; 210/512 M [51] Int. Cl. B04c 3/06 [58] Field ofSearch 209/144, 211; 210/512 R, 210/512 M; 138/42 [56] References CitedUNITED STATES PATENTS 1,711,270 4/1929 Litle 138/42 1,915,867 6/1933Penick 138/42 2,634,741 4/1953 Fontein 209/211 X 2,653,801 9/1953Fontein et al.... 259/4 2,671,560 3/1954 Fontein et al.... 209/2112,743,815 5/1956 Goodwin 209/211 2,776,053 1/1957 Krebs 209/2112,843,265 7/1958 Rakowsky 209/211 X 3,277,926 10/1966 Skardal 209/211 X3,306,357 2/1967 Cullen et a1. 138/42 X FOREIGN PATENTS OR APPLICATIONS990,229 9/1951 France 209/21 1 Primary ExaminerFrank W. Lutter AssistantExaminer-Ralph J. Hill Attorney, Agent, or F irmPravel & Wilson [5 7]ABSTRACT Cylindrical cyclone centrifuges wherein the heavy phase outletis controlled so as to obtain efficient separation of the heavy phasefrom the light phase in a feed such as oil well drilling mud having suchcomponents and so as to inhibit undesirable plugging of the outlet forthe heavy phase.

6 Claims, 8 Drawing Figures CYLINDRICAL CYCLONE CENTRIFUGES BACKGROUNDOF THE INVENTION The field of this invention is cyclone centrifuges.

In the past, cyclone centrifuges have been formed with a conical bodyand a cylindrical body. Although the cylindrical centrifuges have somedefinite advantages over conical centrifuges, such as better separationof the heavy phase solid particles from the light phase solid particles,less turbulence, and more orderly flow therethrough, the cylindricalcentrifuges have had relatively limited use because the solids havetended to plug the outlet opening.

SUMMARY OF THE INVENTION The present invention relates to cylindricalcyclone centrifuges having means for separating heavy phase solidparticles from light phase solid particles in a fluid flowing throughthe centrifuge, wherein the size of the discharge outlet for the heavyphase is great enough for the discharge of the heavy phase in fluid fromthe centrifuge without plugging the outlet, and wherein more effectiveseparation is accomplished than with comparable conical centrifuges.

The invention specifically includes a cluster of cylindrical separatorsconnected to a common heavy phase control means, whereby the heavy phasedischarge is regulated by a single adjustable choke.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a cylindricalcentrifuge of the type preferably used in the apparatus of thisinvention;

FIG. 2 is an elevation of the centrifuge of FIG. 1, showing furtherdetails thereof;

FIG. 3 is an elevation of a vortex regulating device which is connectedto the heavy phase discharge outlet of the cyclone centrifuge of FIGS. 1and 2;

FIG. 3A is a side view of the vortex regulating device of FIG. 3;

FIG. 4 is a view, partly in section and partly in elevation, showing amodified form of the heavy phase discharge control unit which may beused in place of that illustrated in FIG. 3 at the heavy phase outlet ofthe cyclone centrifuge of FIGS. I and 2;

FIG. 5 is another form of a heavy phase control unit which may be usedin place of the devices of FIGS. 3 and 4 for controlling the pressuredrop and the discharge of the heavy phase discharge from the cyclonecentrifuge of FIGS. 1 and 2;

FIG. 6 is a horizontal sectional view, illustrating a plurality ofcylindrical cyclone centrifuges, each of which may be identical to thecentrifuge of FIGS. 1 and 2, and the section line being taken on lines6--6 of FIG. 2 for each of the centrifuges, and with each of thecentrifuges being connected to a common control unit for controlling theheavy phase discharge from the centrifuges; and

FIG. 7 is a sectional view taken on line 77 illustrating further detailsof one form of the heavy phase discharge control unit connected to theplurality of centrifuges.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, the letter Cdesignates generally a cylindrical cyclone centrifuge which is adaptedto receive a fluid such as drilling mud in liquid form having therewithsolid particles which are to be separated into a light phase and a heavyphase by a cyclone flow through the centrifuge C. The present inventionincludes a heavy phase control means H-1, H-2, or H-3 for creating apredetermined pressure drop in the fluid discharging with the heavyphase solid particles so that the discharge outlet from the centrifuge Cmay be large enough to inhibit plugging thereof with the solidparticles, while at the same time avoiding interference with the cycloneseparation in the centrifuge C. In one embodiment of the invention, aplurality of centrifuges C (FIGS. 6 and 7) are mounted in a cluster,with the discharge of the heavy phase solid particles connected to acommon control unit I-I-4.

The cyclone centrifuge C of FIGS. 1 and 2 includes a cylindrical tank 10which has a closed upper end 11. An inlet pipe 12 is connected near theupper end of the tank 10 for introducing mud or other liquid with thesolid particles to be separated tangentially so as to initiate thecyclone flow of the fluid through the tank 10.

The lower end of the tank 10 is closed as indicated by a bottom 14,except for a light phase outlet tube 15 in such bottom 14. As will bewell understood, because of the cyclone action in the tank 10, theheavier solid particles move towards the outer vertical wall of the tank10 and the lighter solid particles remain towards the center portion ofthe fluid as it moves in its cyclone path within the tank 10 so thatwhen the fluid discharges at the lower end of the tank 10, the fluidportion at the center part of the tank 10 exits through the tube 15 andis largely lightweight particles, and in some cases substantially allliquid with very little of the solid particles. The solid particles onthe other hand are discharged through a discharge outlet 18 which iswelded or otherwise secured to the vertical wall of the cylindrical tank10 so that it is in communication with the fluid internally of the tank10 for the discharge of the heavy phase solid particles and liquidtherewith.

Because of the unidirectional flow throughout the centrifuge C, there isa much better separation of the solid particles than with the conecyclone centrifuges. There is also less turbulence and a more orderlyflow of the fluid as it flows through the centrifuge C.

The size of the opening 18 is very important. If it is so small that thesolid particles accumulate and plug it, the centrifuge will becomeinoperative after relatively short periods of time. On the other hand,if the opening in the pipe 18 is excessive, the cyclone separationwithin the centrifuge C is interfered with because too much of the solidparticles exit through the discharge opening with the heavy phase. Ithas been found that such problem can be solved by the connection of aheavy phase control unit or means such as the unit I-I-1 with thedischarge outlet 18.

The control unit H-l has an inlet tube 20 which is connected to theheavy phase discharge outlet 18 as indicated by the dash dot line in thedrawings. The inlet tube 20 is welded or is otherwise mounted with avortex regulating chamber 21 which has a discharge tube 22 at itscentral portion opposite the inlet 20. A free vortex is created withinthe chamber 21 in the known manner so that the fluid and solid particlesdischarging from the discharge tube 22 are essentially confined in anarrow ring in the outer portion of the tube 22, and with the centralcore of the vortex being formed by air which rushes in as a result ofthe vacuum created by the cyclone. Thus, the tube 22 acts as a choke ororifice.

Normally, approximately one velocity head will be expended in creatingthe free vortex in the chamber 21, but on the other hand, the pressuredrop resulting from the discharge through the outlet tube 22 whichserves as an orifice will be extremely high, considerably more so thanthe one velocity head. Therefore, the restricted discharge of the fluidfrom the heavy phase outlet 18 through the unit I-I-1 creates a pressuredrop ofa predetermined amount so that the cyclone separation in theseparator centrifuge C is not disturbed or interfered will but at thesame time the discharge tube 18 and all tubes such as 20 and 22 arelarge enough so that the danger of plugging or closing them with thesolid heavy phase particles is inhibited and usually prevented.

In FIG. 4 another form of control unit I-I-2 is illustrated, wherein aconduit 25 preferably connected directly to the discharge outlet 18 andhaving a diameter substantially the same size as the outlet 18, isformed with a series of sharp bends or angles. Such angles or bendscreate a back pressure and thus a predetermined pressure drop so thatthe size of the orifice 18 is large enough to prevent plugging thereofwhile at the same time the pressure of the fluid in the cyclonecentrifuge C is not disturbed so that effective separation of the solidstakes place.

In FIG. 5, a modified control unit H-3 is illustrated and it has aconduit which is adapted to be considerably connected to the dischargeoutlet 18. The size of the opening in the conduit 30 at the point ofconnection to the discharge outlet 18 is preferably the same or greater,and such conduit 30 is provided with a series of enlargements 31 withthe conduit 30 being formed therebetween and at the outlet or dischargeend. The enlargements 31 in conjunction with the conduits 30 of thesmaller size therebetween, create a back pressure so that apredetermined pressure drop is provided for the discharging heavy phasesolids and the liquid therewith so that the separation in the centrifugeC is not adversely affected and the plugging of the discharge outlet 18is prevented or inhibited.

Although the size of the opening in the discharge outlet 18 for theheavy phase solids and the liquid therewith may vary depending uponoperating conditions, for the guidance of those skilled in the art, thefollowing is exemplary of the range of sizes which would be satisfactoryunder normal operating conditions for a drilling mud separation whereinit is desired to separate substantially all of the solid particles withthe heavy phase discharge.

It has been found that for ordinary cylindrical centrifuges which do nothave a control unit such as H-l through H-5 therewith. the maximum sizeof the open ing in the outlet 18 for effective separation of the heavyphase is not more than about 0.1 inch. With the present invention, usingone of the control units H-l through H-3, the opening in the outlet 18may be at least double the opening size without such a control unitunder the same operating conditions. With the cluster arrange ment usingthe control unit H-4, the orifice opening 53a preferably is within therange of from about 0.35 to about 1.5 inches, and each outlet 18 may beany convenient size within such range. Thus, the opening in outlet 18 isgreatly increased as compared to the prior art, and such increased sizeeffectively eliminates plugging of the outlet 18 or discharge of theheavy phase solids. It also results in an extremely dry discharge ofsuch heavy phase solids so that most of the liquid goes out through thepipe 15. It should be understood that the invention should not belimited to the foregoing sizes or size range because such sizes dependon a number of variable factors such as the pressure, fluid flow ratethrough the centrifuge and the density of the solids in the liquid.However, the foregoing range does emphasize the advantages of thepresent invention and particularly, the ability to use a larger outletthan heretofore was used so as to inhibit or prevent plugging thereofwhile still getting effective separation.

In FIG. 6, a cluster or assembly of cyclone centrifuges C, each of whichis preferably identical to that illustrated in FIGS. 1 and 2, are shownconnected to a common control unit H-4. The sectional view for each ofthe cylindrical centrifuges C in the cluster of FIG. 6 is taken alonglines 66 of FIG. 2.

The control unit H4 is preferably formed with a body having a closedupper end 51 and an open lower end 52 which is adapted to receive areplaceable orifice member 53. The orifice or choke 53 is preferablyheld in position in the body 50 by a removable snap ring 54 mounted inan annular groove 50a in the known manner. The orifice or choke 53 hasan opening 530 through which all of the heavy phase discharge from thecylindrical centrifuges C passes. The opening in such choke 53a ispreferably at least as large as the inside diameter or opening in eachof the heavy phase discharge outlets 18 with each centrifuge C.

It is to be noted that each of the discharge outlets 18 is threaded oris otherwise secured in a suitable opening in the side wall of the body50. The other end of each outlet tube 18 for each cylinder 10 is weldedor is otherwise secured to the cylinder 10.

By having all of the centrifuges C in the luster to FIG. 6 connectedwith a common control unit I-I-4, the back pressure or pressure drop ofthe heavy phase discharge may be controlled for all of such centrifugesC by the single choke 53 so that there is an adequate size for thedischarge outlets 18 to prevent plugging thereof with the heavy phasesolids and at the same time, efficient separation occurs in the cyclonecentrifuges C.

The foregoing disclosure and description of the invention areillustrative and explanatory thereof, and various changes in the size,shape, and materials as well as in the details of the illustratedconstruction may be made without departing from the spirit of theinvention.

I claim:

1. Cyclone centrifuge apparatus, comprising:

a cylindrical separator tank having an upper inlet and a lower outlet,and a cylindrical vertical tank wall, which is entirely cylindrical,between said inlet and said outlet;

means for directing a feed fluid having solid particles of variousweights therewith from said inlet in a direction to create a cycloneflow of such fluid within said tank to effect a separation of the solidparticles into a heavy phase near said wall of said tank and a lightphase towards the center of said tank;

said tank having a closed lower end with said lower outlet for thedischarge of the light phase from said tank;

a heavy phase fluid outlet in the wall of said tank near its lower endfor the discharge of the heavy phase of the solid particles; and

heavy phase control means connected to said heavy heavy fluid outletonly and having a plurality of means therewith for creatingsubstantially equal successive pressure drops in the fluid dischargingfor thereby creating a predetermined pressure drop in the fluiddischarging with said heavy phase with an adequate size for said outletto inhibit plugging thereof with solid particles in said heavy phasewhile the same time avoiding an excessive pressure drop which wouldinterfere with the cyclone separation in said cylindrical separatortank.

2. The centrifuge set forth in claim 1, wherein said means for creatingsaid substantially equal successive pressure drops in said heavy phasecontrol means includes:

a tubular conduit having a single passage therethrough with a series ofsharp turns in said passage terminating in an exit for the fluid withsaid heavy phase.

3. The centrifuge set forth in claim 1, wherein said heavy phase controlmeans includes:

a tubular conduit having a series of longitudinally spaced enlargementswith passages therebetween, with each passage having substantially thesame cross-sectional area as the other passages, and an outlet fromwhich the fluid with the heavy phase discharges.

4. Cyclone centrifuge apparatus, comprising:

a plurality of cylindrical cyclone centrifuges;

each of said centrifuges having a cylindrical tank with an upper inletand a lower outlet, and with a cylindrical vertical tank wall which isentirely cylindrical between said inlet and said outlet, means fordirecting a feed fluid having solid particles of various sizes therewithfrom each said inlet in a direction to create a cyclone flow of suchfluid within said tank to effect a separation of the solid particlesinto a heavy phase near said wall of said tank and a light phase towardsthe center of said tank; a light phase outlet opening in the bottom ofthe tank, and a heavy phase outlet in the wall near the bottom; and

a single heavy phase control unit connected to the heavy phase outletfrom each of said centrifuges by a flow line which is at least as largeas said outlet and which has means for creating a predetermined pressuredrop in the fluid discharging with said heavy phase from each centrifugewith an adequate size for each of said heavy phase outlets to inhibitplugging thereof while at the same time avoiding an excessive pressuredrop which would interfere with the cyclone separation in each of saidcentrifuges.

5. The apparatus set forth in claim 4, wherein:

said control unit has a single outlet with a choke therein through whichall of the heavy phase solids from said centrifuges are discharged.

6. The apparatus set forth in claim 5, wherein:

said choke is adjustable for adjusting the amount of said predeterminedpressure drop in the heavy phase discharge from said centrifuges.

l l l

1. CYCLONE CENTRIFUGE APPARATUS, COMPRISING: A CYLINDRICAL SEPARATORTANK HAVING AN UPPER INLET AND A LOWER OUTLET, AND A CYLINDRICALVERTICAL TANK WALL, WHICH IS ENTIRELY CYLINDRICAL BETWEEN SAID INLET ANDSAID OUTLET, MEANS FOR DIRECTING A FEED FLUID HAVING SOLID PARTICLES OFVARIOUS WEIGHT THEREWITH FROM SAID INLET IN A DIRECTION TO CREATE ACYLONE FLOW OF SUCH FLUID WITHIN SAID TANK TO EFFECT A SEPARATION OF THESOLID PARTICLES INTO A HEAVY PHASE NEAR SAID WALL OF SAID TANK AND ALIGHT PHASE TOWARDS THE CENTER OF SAID TANK, SAID TANK HAVING A CLOSERLOWER END WITH SAID LOWER OUTLET FOR THE DISCHARGE OF THE LIGHT PHASEFROM SAID TANK, A HEAVY PHASE FLUID OUTLET IN THE WALL OF SAID TANK NEARITS LOWER END FOR THE DISCHARGE OF THE HEAVY PHASE OF THE SOLIDPARTICLES, AND HEAVY PHASE CONTROL MEANS CONNECTED TO SAID HEAVY HEAVYFLUID OUTLET ONLY AND HAVING A PLURALITY OF MEANS THEREWITH FOR CREATINGSUBSTANTIALLY EQUAL SUCCESSIVE PREASURE DROPS IN THE FLUID DISCHARGINGFOR THEREBY CREATING A PREDETERMINED PRESSURE DROP IN THE FLUIDDISCHARGING WITH SAID HEAVY PHASE WITH AN ADEQUATE SIZE FOR SAID OUTLETTO INHABIT PLUGGING THEREOF WITH SOLID PARTICLES IN SAID HEAVY PHASEWHILE THE SAME TIME AVOIDING AN EXESSIVE PRESSURE DROP WHICH WOULDINTERFERE WITH THE CYCLONE SEPARATION IN SAID CYLINDRICAL SEPARATORTANK.
 2. The centrifuge set forth in claim 1, wherein said means forcreating said substantially equal successive pressure drops in saidheavy phase control means includes: a tubular conduit having a singlepassage therethrough with a series of sharp turns in said passageterminating in an exit for the fluid with said heavy phase.
 3. Thecentrifuge set forth in claim 1, wherein said heavy phase control meansincludes: a tubular conduit having a series of longitudinally spacedenlargements with passages therebetween, with each passage havingsubstantially the same cross-sectional area as the other passages, andan outlet from which the fluid with the heavy phase discharges. 4.Cyclone centrifuge apparatus, comprising: a plurality of cylindricalcyclone centrifuges; each of said centrifuges having a cylindrical tankwith an uppeR inlet and a lower outlet, and with a cylindrical verticaltank wall which is entirely cylindrical between said inlet and saidoutlet, means for directing a feed fluid having solid particles ofvarious sizes therewith from each said inlet in a direction to create acyclone flow of such fluid within said tank to effect a separation ofthe solid particles into a heavy phase near said wall of said tank and alight phase towards the center of said tank; a light phase outletopening in the bottom of the tank, and a heavy phase outlet in the wallnear the bottom; and a single heavy phase control unit connected to theheavy phase outlet from each of said centrifuges by a flow line which isat least as large as said outlet and which has means for creating apredetermined pressure drop in the fluid discharging with said heavyphase from each centrifuge with an adequate size for each of said heavyphase outlets to inhibit plugging thereof while at the same timeavoiding an excessive pressure drop which would interfere with thecyclone separation in each of said centrifuges.
 5. The apparatus setforth in claim 4, wherein: said control unit has a single outlet with achoke therein through which all of the heavy phase solids from saidcentrifuges are discharged.
 6. The apparatus set forth in claim 5,wherein: said choke is adjustable for adjusting the amount of saidpredetermined pressure drop in the heavy phase discharge from saidcentrifuges.